Open label study of ambrisentan in patients with exercise pulmonary hypertension

Segrera SA, Lawler L, Opotowsky AR, Systrom D, Waxman AB.

Pulm Circ. 2017 Apr-Jun;7(2):531-538. doi: 10.1177/2045893217709024. Epub 2017
May 12.

A growing body of evidence suggests that exercise pulmonary hypertension (ePH) is
an early form of pulmonary arterial hypertension (PAH). Identifying the disease
at an early, potentially more responsive phase, and initiating treatment may
improve functional status and prevent progression to severe forms of PAH.
This was a single-center, open-label six-month treatment trial to evaluate the effect
of ambrisentan on pulmonary hemodynamics and exercise capacity in ePH utilizing
invasive cardiopulmonary exercise testing (iCPET). After six months of treatment
with ambrisentan, patients repeated iCPET; exercise capacity, symptoms, and
pulmonary hemodynamics were reassessed. Twenty-two of 30 patients completed the
treatment phase and repeat iCPET. After six months of treatment there was a
significant decline in peak exercise mPAP (-5.2 ± 5.6 mmHg, P = 0.001), TPG
(-7.1 ± 8.0 mmHg, P = 0.001), PVR (-0.9 ± 0.7 Woods units, P = 0.0002), and
Ca-vO2 (-1.8 ± 2.3 mL/dL, P = 0.0002), with significant increases in peak PCWP
(+2.9 ± 5.6 mmHg, P = 0.02), PVC (+0.8 ± 1.4 mL/mmHg, P = 0.03), and CO
(+2.3 ± 1.4 L/min, P = 0.0001). A trend toward increased VO2max (+4.4 ± 2.6%
predicted, P = 0.07) was observed. In addition, there were improvements in 6MWD
and WHO FC after 24 weeks.
Our findings suggest that treatment of ePH with
ambrisentan results in improved pulmonary hemodynamics and functional status over
a six-month period. Treatment of ePH may prevent the progression of vascular
remodeling and development of established PAH.